I can't tell if it's genuine or not, but I don't see anything that suggests it not what claims to be. The packaging looked pretty good, and the printed documentation is high-quality, but when it comes down to it, it's a piece of metal with puffy stickers attached to it.
In any case, it did the job well. The metal is flexible, but doesn't seem to deform. For what it does, it's perfect. I'm glad I bought it.
I haven't, personally. But I would think it would be useful for any tightly seamed snap joints. Actually, I just gave it a go on my XBox controller and, yes, once you remove the six screws, it will work like a charm.
The Middle portion is very rubbery and flexible. The tip and end are very thin but feel durable enough, I have not put them under serious pressure to see how resistant to bending pressure they are though.
Yes, The tool will get into the small seam that allows you to open the MacBook Air. Just make sure you know where you are using it, and that you find a tutorial that shows you how to open it. i used it to open my iPad 2(tough battle), and it worked well.